1. Technical Field
The present invention generally relates to a lens shutter type of auto-focus camera, and more particularly to a zoom lens type of camera in which a zoom lens system is used as a taking or photographing optical system, and in which a finder optical system and an electronic flash device (i.e., a strobe) are associated with the zooming operation of the zoom lens system. In other words, the finder optical system and the strobe move in coordinated fashion with zooming movement of the lens.
This application is related to the commonly assigned application filed on even date herewith, Application Ser. No. 143,946, entitled "Zoom Lens Drive System for lens shutter type of Camera", Jan. 7, 1988, now U.S. Pat. No. 4,936,664, the disclosure of which is expressly incorporated by reference herein.
2. Background Art
Generally, in conventional lens shutter (i.e., between the lens shutter) types of auto focus cameras, it is impossible to vary the focal length of the photographic optical system. Other lens shutter types of auto focus cameras comprise a two focal length system, in which a lens is provided for varying the focal length and can be selectively inserted in the photographing optical system. In such a system, two focal lengths are provided; however, it is possible to use only the two focal lengths provided, e.g., a wide angle and a telephoto range for the zoom lens, or, e.g., a standard range and a telephoto range for the zoom lens. While taking advantage of such dual focal lengths, it is impossible to cover the range of focal lengths between the two extreme focal lengths, or between a wide angle and a medium telephoto focal length. Under such circumstances, taking pictures with the use of a zoom lens has heretofore only been possible by using a single lens reflex camera.
However, single lens reflex cameras are more expensive and heavier than lens shutter type cameras, and, accordingly, it is not easy for a photographer who is unfamiliar with cameras to freely use such single lens reflex cameras. Because of the heavy weight and relatively large size of such single lens reflex cameras, female photographers and travelers who are desirous of reducing the weight and the amount of baggage carried tend to hesitate to use such a single lens reflex (hereinafter SLR) camera, even if they appreciate the high quality pictures which are generally taken by such cameras.
Accordingly, users who would otherwise hesitate to use single lens reflex cameras which are relatively bulky and heavy, as noted above, have only two alternate choices: (a) a relatively small, light lens shutter type of automatic camera which has heretofore not been capable of controlling the focal length of the photographing optical system; or (b) a dual focal length type of auto focus camera in which only two extreme focal lengths can be used.
In view of such circumstances, one primary object of the present invention is to provide a small, light, compact lens shutter type of camera with a zoom lens in which focusing control and electronic flash or strobe control can be automatically effected.
Another object of the present invention is to provide a lens shutter type of auto-focus camera which has an additional macro (i.e., close-up) function with which an extremely large, detailed image can be taken; and in which a finder optical system and an electronic flash device are adapted to be coordinated with zooming operation of the zoom lens in the macro mode as well as in normal operation (e.g., in wide angle, telephoto or standard operation).
Yet another object of the present invention is to provide a movable macro compensating optical element which is used in the distance measuring apparatus or range finder in order to extend the optical base length from its value in the normal photographic mode, and to enable substantially the same area on the position detecting sensor to receive light when measuring the distance of a subject.
Still another object of the present invention is to provide a camera having a field of view with minimum parallax in the macro mode.
Another object of the present invention is to reduce parallax in a lens shutter type camera by providing a prism selectively movable into the path of a finder optical system in order to deflect the field of view downwardly and rightwardly to the axis of the photographing optical system when the camera is in its macro photographing mode.
Still a further object of the present invention is to move a strobe lamp assembly along an optical axis thereof in coordination with movement of a zoom lens.
Yet another object of the present invention is to provide a distance measuring device used in an auto-focus lens shutter type of camera in which an optical wedge is selectively inserted to extend the optical base length between the light emitter and the light receiver comprising the distance measuring device.
Still another object is to provide a finder optical system in which it is necessary to move only a single lens to vary the field of view.
Another object is to provide a lens shutter type camera with a light intercepting assembly which minimizes light from entering a photographic optical assembly lens system.
Still a further object of the present invention is to provide a lens shutter type of camera which includes a strobe assembly whose illumination angle varies in accordance with the position of a movable zoom lens assembly.
Yet another object of the present invention is to provide a lens shutter type camera in which a flexible printed circuit board is guided in its movement along one side of a cam ring and zoom lens, and which includes strucure for minimizing internal reflections from the FPC board into the interior of a photographing optical assembly.